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[helm.git] / helm / software / matita / help / C / sec_commands.xml

diff --git a/helm/software/matita/help/C/sec_commands.xml b/helm/software/matita/help/C/sec_commands.xml
index 4fe77d7b78a8dc3e4871322b5d6a5c736ce11ccb..4d788f39aa3feb8ed01961dd48a782b9ec2a6436 100644 (file)
--- a/helm/software/matita/help/C/sec_commands.xml
+++ b/helm/software/matita/help/C/sec_commands.xml
@@ -76,24 +76,34 @@
  </sect1>
  <sect1 id="command_coercion">
    <title>coercion</title>
-   <para><userinput>coercion u</userinput></para>
+   <para><userinput>coercion u with ariety saturation nocomposites</userinput></para>
    <para>
      <variablelist>
        <varlistentry>
          <term>Synopsis:</term>
          <listitem>
-           <para><emphasis role="bold">coercion</emphasis> &uri;</para>
+                <para>
+                        <emphasis role="bold">coercion</emphasis> 
+                        (&uri; | &term; <emphasis role="bold">with</emphasis>)
+                        [ &nat; [&nat;]] 
+                        [ <emphasis role="bold">nocomposites</emphasis> ]
+                </para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term>Action:</term>
          <listitem>
-           <para>Declares <command>u</command> as an implicit coercion
-            from the type of its last argument (source)
-            to its codomain (target). Every time a term <command>x</command>
+                <para>Declares <command>u</command> as an implicit coercion.
+                If the type of <command>u</command> is         
+                <command>∀x1:T1. … ∀x(n-1):T(n-1).Tn</command> the coercion target is
+                <command>T(n - ariety)</command> while its source is 
+                <command>T(n - ariety - saturation - 1)</command>.
+           Every time a term <command>x</command>
             of type source is used with expected type target, Matita
             automatically replaces <command>x</command> with
-            <command>(u ? … ? x)</command> to avoid a typing error.</para>
+            <command>(u ? … ? x ? … ?)</command> to avoid a typing error.</para>
+            Note that the number of <command>?</command> added after 
+           <command>x</command> is saturation.
            <para>Implicit coercions are not displayed to the user:
             <command>(u ? … ? x)</command> is rendered simply
             as <command>x</command>.</para>
@@ -102,7 +112,8 @@
             and there is already a coercion <command>u'</command> of
             target <command>s</command> or source <command>t</command>,
             a composite implicit coercion is automatically computed
-            by Matita.</para>
+           by Matita unless <emphasis role="bold">nocomposites</emphasis> 
+           is specified.</para>
          </listitem>
        </varlistentry>
      </variablelist>